1. Field of the Invention
The present invention relates to an integrated coal liquefaction and gasification process.
2. Description of the Prior Art
Coal liquefaction processes in which coal with or without a diluent is subjected to elevated temperatures and pressures to convert the coal to normally liquid hydrocarbonaceous products are well known. Coal liquefaction processes in which coal is converted in the presence of a hydrogen donor diluent with or without added molecular hydrogen are also known. See, for example, U.S. Pat. No. 3,841,991, the teachings of which are hereby incorporated by reference.
It is also known to liquefy coal in the presence of a vapor phase solvent which comprises a hydrogen donor, see for example, U.S. Pat. No. 3,997,424 and U.S. Pat. No. 4,036,731.
U.S. Pat. No. 3,692,662 discloses a staged coal liquefaction process in which a slurry of coal in a solvent, such as a hydrogen donor solvent, is maintained at a temperature below 700.degree. F. to effect formation of a dispersion, and thereafter, the dispersed slurry is heated to a temperature above 700.degree. F.
U.S. Pat. No. 3,791,957 discloses a coal pretreatment at a pressure in excess of 1000 psig in the presence of added hydrogen at a temperature from 600.degree. to 750.degree. F. followed by catalytic ebullating bed coal hydrogenation.
U.S. Pat. No. 3,970,541 discloses a process for a gas extraction of coal. The coal and solvent are heated to 370.degree. C. at a rate of 20.degree. C. per minute and, thereafter, to 400.degree.-500.degree. C. at a rate less than 10.degree. C. per minute. The solvent is preferably in the gas phase over the greater part of the range in which the slower rate of heating is performed.
It is also known to produce liquid hydrocarbons by a fluid coking process in which coal particles are slurried in a hydrogen donor solvent as disclosed in U.S. Pat. No. 3,841,991. Fluid coking of coal in a water slurry is also known. See, for example, U.S. Pat. No. 3,272,720.
It is also known to gasify solid carbonaceous materials by treatment with steam and an oxygen-containing gas under gasification conditions to produce a hydrogen-containing gas.
It has now been found that an integrated coal preswelling, coal liquefaction and gasification process results in advantages that will become apparent in the ensuing description.